JP2636444B2 - Antenna device for mobile communication - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device for mobile communication, and more particularly to a mobile communication device capable of sharing the radiation of communication radio waves for both satellite communication and terrestrial communication with one antenna. The present invention relates to an antenna device for use in a vehicle.

[Conventional technology]

Recently, the development of mobile communication has been remarkable, on land, at sea,
In addition to air-to-ground communications, mobile satellite communications via artificial satellites are becoming commonplace. The usage status of such multipurpose mobile communication is described in the fourth section.
This is shown in the explanatory diagram of the figure. FIG. 4 shows an antenna 11 dedicated to ground communication for communication between a ship 17 or an aircraft 13 and a ground station 18 as a mobile unit.
For communication via artificial satellite 16, large and expensive antennas for satellites 10 with high gain and tracking function are also individually arranged, making it a large system. There is a feeling that is limited. By the way, when looking at the future, the pattern of the artificial satellite becomes larger, and further higher performance is desired. In particular, by the large and multi-beam antenna installed on the satellite 16,
It is anticipated that the antenna 14 for the mobile unit on the user side will be small and low-gain, and that the mobile unit will be able to perform mobile communication via artificial satellites as well as modern ground-based mobile communication.

[Problems to be solved by the invention]

However, in the conventional mobile communication antenna described above, the terrestrial communication antenna and the satellite communication antenna are separately provided, and the antenna for satellite communication is large, so that economical future mobile communication is required. The form also has problems.

An object of the present invention is to provide an antenna for mobile communication in which the antenna of the mobile is small and the radiation characteristics suitable for both ground communication and satellite communication can be obtained with one antenna.

[Means for solving the problem]

An antenna device for mobile communication according to the present invention includes a mobile object, a satellite communication device (referred to as a first device), a ground communication device (referred to as a second device), and the second device. An antenna for mobile communication having an antenna for radiating communication signals input and output from the first and second devices into space, a center installed on the mobile so that the antenna is substantially perpendicular to the ground surface. An omnidirectional radiation pattern is generated on a plane parallel to the ground surface which has an axis and is substantially perpendicular to the central axis direction, and the radiation pattern is generated in a plane perpendicular to the ground surface including the central axis. A single antenna that directs a high elevation angle with respect to the ground surface in a high frequency band and directs a low elevation angle with respect to the ground surface in a low frequency band, and communicates a communication signal input / output from a feeder of the antenna to the first antenna. Demultiplexing for each of the first and second devices Preliminary EXAMPLES comprises a demultiplexer for combining the present invention will now be described with reference to the drawings.

 FIG. 1 is a configuration diagram of one embodiment of the present invention.

The embodiment of FIG. 1 shows a conical monopole antenna 1 having both directional characteristics 1A for satellites and directional characteristics 1B for ground, and VHF to UHF transmission / reception frequency bands for ground.
Frequency band (hereinafter f _L ~3f _L band hereinafter) as well as transmitting and receiving frequency band for anti-satellite UHF~ microwave frequency band (hereinafter 5f _L
), A broadband electromagnetic wave that connects between the antenna 1 and the duplexer 2 is transmitted. And a moving body 6 for mounting these devices.

Next, the operation of a single element antenna which is one of the basic forms of the antenna 1 will be described with reference to the explanatory diagram of FIG. 2 and the radiation pattern characteristic diagram of the single element antenna of FIG.

Normally, the elevation angle at which a terrestrial mobile unit detects a mobile communication satellite in geosynchronous orbit depends on the latitude on the earth,
For example, in the case of Japan (30 ° to 50 ° north latitude), the elevation angle is about 32 ° to 55 °. In other words, as the characteristics of the antenna, if the directivity of the half width of the power of the radiation characteristic is 30 ° to 40 ° at an elevation angle of 45 ° and the directivity in the horizontal plane is omnidirectional, the satellite is forcibly tracked as a mobile antenna. The communication line can be maintained without any problem. As an antenna device meeting such conditions, a single element antenna is a typical antenna having a non-directional characteristic in a horizontal plane. Now, this single element antenna has f _L
And an electromagnetic wave of the electromagnetic wave and 5f _L band ～3F _L band are excited by a current distribution as shown in Figure 2. Figure 3 shows the radiation pattern of the vertical plane directivity of the electromagnetic wave excited as this, in the range of about 3f _L from band lowest frequency f _L, the maximum radiation direction is horizontal, in about 5f _L to about The 45 ° direction is the maximum. That is, if the band is widened by a single element antenna,
It can be adapted to this antenna device. Although various means for realizing this are conceivable, a conical monopole antenna is suitable for the antenna element. Alternatively, a multi-frequency matching unit may be added to a single element antenna. In this type of antenna, there is a frequency condition to obtain the required radiation characteristics,
Generally, the frequency used for mobile communication is VH for ground communication
F to UHF (50MHz to 800MHz), U for satellite communication
HF to microwaves (800 MHz to several GHz), which are convenient because they can be selected to meet the above-mentioned conditions. The conical monopole antenna 1 is connected to the satellite communication device 3 and the terrestrial communication device 4 via the broadband duplexer 2, respectively. Here car phone case versus ground communication frequencies the f _L of the antenna 1 to 320 MHz, MCA, and 800MHz are often used in personal wireless, etc., when to assign a 1.6GHz paired satellite communication frequencies, each of the communication Suitable directional characteristics are obtained.

〔The invention's effect〕

As described above, the present invention uses a simple antenna represented by a conical monopole and a broadband duplexer to transmit and receive radio waves having directional characteristics suitable for ground communication and satellite communication. be able to. Therefore, there is an effect that it is possible to provide a mobile communication antenna apparatus suitable for the mobile communication prosperity era to arrive in the future.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIGS.
The figure is an explanatory diagram and a characteristic diagram of the antenna including the present embodiment.
The figure is an explanatory diagram showing a usage form of general mobile communication. DESCRIPTION OF SYMBOLS 1 ... Antenna, 2 ... Divider, 3 ... Communication equipment for satellite, 4 ... Communication equipment for ground, 5 ... Power supply cable, 6
… Mobile object, 7… single element antenna, 1A… directional characteristic for satellite, 1B… directional characteristic for ground.

Claims (1)

(57) [Claims] 1. A mobile object, a device for communication with artificial satellites (referred to as first device), a device for communication with ground (referred to as second device), and the first and second devices mounted on the mobile object. And an antenna for radiating a communication signal input and output from the antenna to a space, wherein the antenna has a central axis installed on the mobile so that the antenna is substantially perpendicular to the ground surface. An omnidirectional radiation pattern is generated on a plane parallel to the ground surface, which is a plane substantially perpendicular to the axial direction, and in a plane perpendicular to the ground surface including the central axis, the radiation pattern is ground at a high frequency band. A single antenna which directs a high elevation angle to the surface and directs a low elevation angle to the ground surface in a low frequency band, and transmits communication signals input and output from a feeder of the antenna to the first and second devices A demultiplexer for demultiplexing and combining each An antenna device for mobile communication, comprising: